Trainee hairdresser Charlie Dunne, 19, took the hormone while boyfriend Terence Rhoden, 28, was at hospital. He found her collapsed at their home when he returned five hours later.

She was rushed to hospital but died six days later after suffering brain damage as a result of an insulin overdose. Police had investigated claims Terence injected her with his insulin pen after the couple heard it helped weight loss. But detectives found no evidence he was involved in his girlfriend’s death.

The inquest heard yesterday that Charlie, from Atherton, Gtr Manchester, was a bubbly girl who regularly went to church. But she also suffered mood swings, claimed she had miscarried a child and was unable to conceive, and had tried to overdose on pills in another relationship.

The night before she died, Charlie had been in a pub with pals before having a panic attack and fleeing home. Mr Rhoden told the hearing Charlie woke him when she got home, told him to leave and said he was “too good for her”.

NIGHT OF TORMENT: Charlie died after using boyfriend Terence’s insulin pen [Facebook]

“It is likely this was a cry for attention that had the most dramatic and catastrophic consequence”

Alan Walsh, Bolton coroner

He added: “She wanted painkillers but I told her she could not take them as she had been drinking. We talked in the living room and she calmed down,” he said.

He left for a hospital appointment at 7am the next day but was worried when she did not reply to his calls and texts. When he came home at noon he found her unconscious on the living room floor and realised she had taken his insulin.

He said: “I saw Charlie breathing heavily. She was blue in the face with foam coming out of her mouth. I thought she was having an allergic reaction.

“I saw my insulin pen on the couch. It was brand new – the box was in the bin but the pen was empty.’’

Charlie died at Royal Bolton Hospital on December 23, last year.

Bolton coroner Alan Walsh recorded a verdict of misadventure, saying Charlie probably gave herself the jab not realising what insulin can do to a non-diabetic. “It is likely this was a cry for attention that had the most dramatic and catastrophic consequence,” he added.